NEW YORK -LRB- CNN -RRB- -- His was one of the first photos of a missing child to appear on a milk carton . Almost 30 years later , Etan Patz is still missing .

Etan Patz , who disappeared in 1979 , was the first missing child featured in the milk carton campaigns of the 1980s .

Etan was 6 when he disappeared on May 25 , 1979 , the Friday before Memorial Day . He was on his way to school in what is now the upscale Soho neighborhood of New York .

It was the first time he 'd walked to the bus stop by himself . It was just a few blocks away . Etan , like any 6-year-old , argued that all of his friends walked to the bus stop alone , and his parents relented .

His mother , Julie Patz , learned that Etan had n't been in classes when he failed to return home . She called the school at 3:30 p.m. , then called the homes of all his friends . When no one had seen Etan , she called police and filed a missing person 's report .

By evening more than 100 police officers and searchers had gathered with bloodhounds . The search continued for weeks , but no clues to Etan 's whereabouts were found . Watch an update on the case ''

The boy 's disappearance was one of the key events that inspired the missing children 's movement , which raised awareness of child abductions and led to new ways to search for missing children . Etan 's case was the first of the milk carton campaigns of the mid-1980s .

`` In our minds there were only two possibilities , '' said Stan Patz , the boy 's father . `` Either Etan was taken by a stranger and killed or he was taken by a very sad woman desperate for a child of her own , and we hoped that such a woman would at least take care of him and keep him safe . ''

Patz lived with this hope until 1982 , when he learned of Jose Antonio Ramos ' arrest and the surprising connection between him and a former babysitter of Etan 's .

Ramos was a drifter who in 1979 lived in Alphabet City , a neighborhood not far from Soho . In 1982 he was arrested after boys in a neighborhood in the Bronx complained that he had stolen their book bags while trying to coax them into a drainpipe under a bridge , where he lived , said the Patzes and federal prosecutor Stuart GraBois , who spent years investigating the case .

When police found Ramos in his drainpipe home , they found he had many photographs of small blond boys . They noticed that they looked a lot like Etan Patz , according to author Lisa R Cohen 's book about the case , `` After Etan : The Missing Child Case that Held America Captive . ''

Bronx police questioned Ramos , and he denied having anything to do with Etan 's disappearance . But he did tell police that his girlfriend used to baby-sit for the boy , GraBois said .

Prosecutors in the Bronx and Manhattan pursued this lead , but concluded they did not have enough evidence to connect Ramos to Etan 's disappearance , GraBois and a spokesperson for the Manhattan District Attorney 's Office said .

Ramos was released when the parents of the Bronx boys chose not to press charges against him , according to published reports . He left town and disappeared for six years -- until GraBois reviewed Etan 's case . GraBois said he focused on Ramos as the prime suspect .

GraBois said he learned in 1988 that Ramos had been arrested and convicted of child molestation and was serving time in a Pennsylvania prison .

GraBois said he brought Ramos to New York for questioning and surprised him with the question : `` How many times did you have sex with Etan Patz ? ''

Ramos told GraBois that he 'd taken a little boy to an apartment he had on the lower East Side on the same day that Etan went missing . `` He was 90 percent sure it was the same he 'd seen in the news that was missing , '' GraBois said .

According to GraBois , Ramos claimed he released the boy and brought him to a subway station so the boy could go visit his aunt in Washington Heights .

`` Etan did not have an aunt in Washington Heights , '' GraBois said . When questioned further , Ramos refused to say anything more and asked for a lawyer , according to GraBois .

Ramos is serving a 10 - to 20-year prison sentence in Pennsylvania . He is scheduled to be released in November 2012 , GraBois said .

GraBois said he had Ramos transferred to a federal prison , and planted informants as his cell mates . He would n't go into detail about what Ramos might have told them , but said he 's convinced he 's eyeing the right suspect .

GraBois turned over his evidence to the Manhattan District Attorney 's Office , but prosecutors have not brought charges . They say that without a body , they do n't have enough evidence .

Etan 's case is still considered by the NYPD to be a cold case .

Anyone with information on the whereabouts of Etan Patz or that leads to the arrest and conviction of the individual responsible for his disappearance is asked to call the FBI/NYPD Etan Patz hotline : 212-384-2200 .

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Boy , 6 , begged his parents to let him walk to school bus stop for first time

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He never showed up at school in Manhattan 's Soho neighborhood

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Etan Patz disappeared on May 25 , 1979

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Know something ? Call the FBI/NYPD Etan Patz hotline : 212-384-2200